A new class of chemicals with anti-androgenic properties have been identified in UK river waters, according to a recent study published in Environmental Health Perspectives. Anti-androgenic chemicals inhibit the normal function of androgens, or male sex hormones that are responsible for male sexual characteristics. The study suggests that these chemicals cause decreased fertility in wildlife, and could have further implications in human reproductive health.

Previous studies have found the presence of chemicals mimicking estrogens, or female sex hormones, in water systems. These chemicals have been suggested as culprits in the increase of fertility problems or even sex changes in male fish. However, the discovery of these chemicals left some questions unanswered, specifically the effect of such chemicals on human male fertility. Scientists suggested the role of water pollutants in human male fertility problems caused by testicular dysgenesis syndrome (TDS), but lacked direct evidence for this correlation, given that TDS is known to be caused by anti-androgen, rather than estrogenic, chemical exposure. TDS is the term used to describe a collection of several symptoms thought to be related, including testicular cancer and decreased sperm quality in men. The newly published results provide stronger evidence for the correlation between water pollution and male fertility problems.

According to senior author Professor Charles Tyler of the University of Exeter, the new study is just one more piece in a growing body of evidence for the link between chemical water pollutants and male reproductive problems. "Our research shows that a much wider range of chemicals than we previously thought is leading to hormone disruption in fish," he said. ".Our findings also strengthen the argument for the cocktail of chemicals in our water leading to hormone disruption in fish, and contributing to the rise in male reproductive problems. There are likely to be many reasons behind the rise in male fertility problems in humans, but these findings could reveal one, previously unknown, factor."

The origins of the anti-androgenic water pollutant are a subject of future research for the paper's authors, including lead author Dr. Susan Jobling at Brunel University's Institute for the Environment. "A principal aim of our work," she said, "is now to identify the source of these pollutants and work with regulators and relevant industry to test the effects of a mixture of these chemicals and the already known environmental estrogens and help protect environmental health."